Fireplaces, particularly wood burning fireplaces, have been a staple of society for centuries, and are a nearly universally popular means for providing warmth to buildings, such as homes, hotels, and restaurants. A recent U.S. Census survey showed that more than 64,000,000 fireplaces have been installed in homes nationwide. A fireplace is the third most popular option for a new house, outranked only by central heating/air conditioning and a two-car garage. The National Association of Realtors says the addition of a fireplace is one of the best returns on investment a homeowner can make. Fireplaces are also increasingly becoming popular for use in outdoor settings like patios, decks, and balconies.
Fireplaces, however, are also known to be relatively inefficient at heating. Common fireplaces at best are only 15%-20% efficient at generating heat. In fact, during some stages of a fire's life, more energy, like the heat in warm air, is taken from the area surrounding the fireplace than is released by the fire itself. Furthermore, cold air from outdoors can enter indoor rooms via the fireplace, making these rooms even colder. With such inefficient heating, users of fireplaces often must stay huddled close to the fire and/or use additional sources of heat to keep warm.
In addition to being inefficient, fireplaces can cause, for example, harmful pollutants including particulates, volatile organic compounds (“VOCs”), and carbon monoxide to be emitted into the atmosphere. These emissions have been linked to adverse health effects, such as lung cancer, and environmental problems like smog and acid rain. Recognizing the environmental problems burning wood can exasperate, the United States Environmental Protection Agency (“EPA”) has placed strict limits on the emissions permitted by wood burning stoves. The limits are currently 7.5 grams of smoke per hour (g/h) for non-catalytic stoves, and 4.1 g/h for catalytic stoves. The EPA is currently instituting new regulations regarding the use of wood burning fireplaces in the U.S. These regulations (e.g., ASTM E06.54) generally limit a fireplace to the release of about 5.1 g of particulates per kg of material burned. To date, no known solutions have been proposed for traditional fireplaces to meet these regulations. Accordingly, devices and methods for reducing combustion emissions generated in, or released from, a combustion chamber are needed.